The present invention relates to a computer simulation method for a macromolecular material, more particularly to a method for converting a unit system used in a molecular dynamics calculation performed by the use of a coarse-grained model into a unit system used in a macromolecular chain of the macromolecular material.
In recent years, in order to develop or design rubber compositions, there has been proposed a computer simulation method for simulating behaviors of a macromolecular material in which a coarse-grained model of a macromolecular chain modeled by a plurality of beads is defined and, using such coarse-grained models disposed in a virtual space, a molecular dynamics calculation to simulate behaviors of the macromolecular chains is performed.
In such a molecular dynamics calculation utilizing a coarse-grained model, a unit system (e.g. time, length, mass, etc.) different from that in the real macromolecular chain is employed. Accordingly, in order to know the actual phenomenon or behaviors expected in the real macromolecular chain from the simulation result based on the coarse-grained model, namely, based on the different unit system, it is necessary to convert the unit system from that in the simulation to that in the real macromolecular chain.
Until now, therefore, through an experiment using the actual macromolecular material, a physical quantity (e.g. relaxation time) of the macromolecular chain is measured. Then, using the obtained physical quantity, the conversion of the unit system is made. Such a conversion based on the experimental result is costly and takes time. Further, if the macromolecular material does not exist yet in reality or is not readily available, the conversion is almost impossible.
As another method to avoid a conversion between different unit systems, it is conceivable to use an all-atom model instead of a coarse-grained model in order to represent a macromolecular chain in a computer simulation method.
In such a method, however, the scale of computation becomes very large, and the computational costly and time are increased.